Vaporized fuel burner with downdraft air supply duct



June 29, 1954 F. P. EDWARDS 2,682,300

VAPORIZED FUEL BURNER WITH DOWNDRAF'T AIR SUPPLY DUCT Filed March 8, 1951 I 2 Sheets-Sheet l INVENTOR.

r. P. EDWARDS ATTORNEY June 29, 1954 F. P. EDWARDS 2,582,300

VAPORIZED FUEL BURNER WITH DOWNDRAFT AIR SUPPLY DUCT Filed March 8, 1951 2 Sheeis-Sheet 2 Q 98 2mm 98 g 90 INVENTOR.

F r. P- EDWARDS 6 BY Patented June 29, 1954 VAPORIZED FUEL BURNER WITH DOWN DRAFT AIR SUPPLY DUCT Felix P. Edwards, Parkton, N. C.

Application March 8, 1951, Serial No. 214,527

1 Claim.

This invention relates to tobacco curing and more particularly to an oil burning stove particularly adapted for use in a tobacco curing warehouse and designed to eliminate or minimize the fire hazards normally present in conjunction with such usage while providing an optimum efficiency of combustion.

Oil burning stoves have been commonly used for heating tobacco curing warehouses, but the types of stoves in common use have had the disadvantages that they were inefficient in their burning of oil and produced excessive smoke and an objectionable odor, or the stove became extremely hot and presented a bad fire hazard in the presence of the relatively dry and easily combustible tobacco leaves which might fall on the hot stove and initiate a general conflagration with the resulting loss of the tobacco crop and curing warehouse, as well as any other warehouses or buildings which might be located nearby.

One object of the present invention is to provide an improved burner forburning liquid hydro-carbons and especially adapted for use in a tobacco curing warehouse.

A still object of the present invention is to provide an improved burner unit which facilitates efficient combustion of liquid hydro-carbons particularly in conjunction with a central downdraft duct supplying air thereto.

The heating unit of the present invention consists essentially of a base having adjustable legs secured thereto adjacent the periphery thereof and having a central opening therethrough, an outer cylindrical shell secured to the base in upright position and having an exhaust opening through one side thereof adjacent the upper portion, a flat plate across the upper end of the cylindrical housing having a central opening therethrough, and a shield mounted above the flat plate in spaced relation thereto. A burner unit is mounted in the'central opening in the base and an inverted frustoconical air inlet extends through the central opening in the top plate and terminates in contiguous spaced relation to the top of the burner unit. The burner unit itself is of novel design and includes a central preheating chamber into which the oil is fed having a plurality of upwardly and outwardly directed jet openings, 2. pair of spaced concentric grooves separated by a raised ridge with an overflow pipe extending out of the inner groove, and two series of air inlet openings extending from the bottom of the burner unit. One series has larger openings extending into the outer groove, and the other series has smaller openings extending through the separating ridge.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings. wherein:

Figure l is a side elevational view of one preferred embodiment of the present invention;

Figure 2, an enlarged longitudinal section taken on the line 2-2 in Figure 1:

Figure 3, a sectional view of the heating unit taken on line 3-3 of Figure 1:

Figure 4, an enlarged top plan view of the burner unit; and

Figure 5, a sectional view of the burner unit taken on line 55 of Figure 4 and also showing the oil inlet and overflow pipes, and the primary air inlet with portions broken away.

Referring now to the drawings in detail and more particularly to Figures 1, 2 and 3, one preferred embodiment of the heating unit of the present invention is shown, wherein the circular base plate Hi is mounted on three legs 12 which are provided with spherical heads it at the lower end and threaded into suitable openings adjacent the periphery of the base plate and may be retained in adjusted position by the lock nuts 16. The base plate I0 is provided with an annular recess IS in which the outer shell 2% of the expansion chamber is seated and retained by angle clips 22 which are secured to the base by machine screws 24 and to the outer shell by bolts and nuts 26.

An opening is provided through the upper portion of the outer shell 20 and a collar 28 is secured'around the periphery thereof. The collar is provided with a lug 30 having a set screw 32 extending therethrough for securing the flue pipe it in position. A deflector 35 in the shape of a frusto-conical section is made preferably of sheet metal and is secured inside the outer shell 20 around the opening opposite the collar 28. An upper plate 36 is suitably secured across the upper end .of the outer shell 2i and is provided with a central opening therethrough for receiving and retaining a downdraft primary air inlet pipe 38.

A plurality of supports 40 are suitably secured to the outer shell and extend a substantial distance above the top plate 36 to support the shield 62. The shield 42 is removably secured to the supports 40 by angle clips 44 which may preferably be welded to-the shield and secured to the supports 40 by metal screws 46. 1

The primary air inlet 38 is preferably of an inverted frusto-eonical shape and has a relatively short portion which extends above the top plate 36 and has a diametrically disposed bolt 50 extending therethrough to serve as a handle to facilitate removal for cleaning and ignition of the burner. The lower and smaller end of the air inlet pipe 38 is provided with a specially formed diametrical bolt 52 which is provided with a flattened intermediate portion 54 having an aperture therethrough.

The burner unit 56 has a peripheral flange 58 which is seated in an annular groove 60 formed around the central opening in the base plate and is secured therein by bolts and nuts 62 or other suitable means. The burner unit 56 is supplied with oil through a suitable conduit 64 extending from a tank or other source of oil (not shown) which is usually provided with a conventional carburetor or float valve (not shown), and is provided with an overflow conduit 66.

The details of the burner unit itself are more clearly shown in the enlarged views of Figures 4 and which also clearly illustrate the flow of primary and secondary air with relation to the jets of vaporized fuel during normal operation of the burner, after it has once been started and sufliciently heated.

The burner 56 is provided with a central vaporizing chamber 68 provided with a threaded opening to receive the threaded end of the conduit 64. A series of jet openings 12 extend upwardly and outwardly from the upper portion of the vaporizing chamber, and the central opening 14 through the upper wall of the vaporizing chamber receives a bolt '18 on which are mounted a plurality of spacing washers 18, a nut 80 and a lock nut 82 which support the primary air inlet pipe 38 in spaced contiguous relation above the burner unit with the bolt 18 extending through the opening in the flattened portion 54 of the bolt 52. It will be obvious that the spacing of the primary air inlet pipe 38 with relation to the upper surface of the burner unit 56 may be varied by the use of any desired number of spacing washerslB.

A pair of annular grooves 84 and 86 separated by a raised annular ridge 88 surrounding the vaporizing chamber 68. A series of relatively large openings 98 extend through the burner from the bottom thereof into the outer groove 86, and a series of smaller openings 92 extend through the burner from the bottom thereof to the top of the ridge 88. Another opening 84 extends from the inner groove 84 into an enlarged threaded bore 96 which receives the threaded end of the overflow conduit 66. The apertures 88 adjacent the periphery of the flange 58 are adapted to receive the bolts 62 for securing the burner unit 36 to the base plate l0.

In the operation of the device the shield 42 and the primary inlet pipe 38 are removed and the flow of oil is started to the vaporizing chamber 68. The oil will overflow through the jet openings 12 into the inner groove 84 and may be lighted by inserting a small piece of burning waste through the central opening in the top plate 36. The air inlet pipe 38 is then replaced in its proper position and the shield 42 secured to the supports 40. When the vaporizing chamber has heated sufiiciently, the oil will be vaporized within the chamber -68 and will be forced out through the jet openings 72 in the form of a fine mist or vapor which meets the down fiow of air through the inlet pipe 38, as indicated by the arrows, and the air miXing With the vaporized oil will form a readily combustible mixture which will immediately ignite and mushroom outwardly due to the flow of air between the lower end of the inlet pipe 38 and the top of the burner 56.

The mushrooming flame thus formed meets with secondary air which flows upwardly through the openings and Q2, as indicated by the arrows, to provide the necessary additional air to promote the most efficient combustion. When optimum combustion has been attained, the flame becomes white, and substantially complete burning of the oil takes place with very little smoke or formation of soot.

The flow of air between the top plate 36 and shield 42 down through the inlet pipe 38 keeps these elements relatively cool at all times, particularly since the flow of air out of the bottom of the inlet pipe 38 tends to mushroom the flame outwardly towards the outer walls.

The hot gases of combustion will obviously rise and flow outwardly around the top and bottom edges of the deflector 35 which tends to hold the heat inside the stove since at least a portion of the hot gases will strike the inclined. surface of the deflector 35 and be forced to pass over the upper edge. The hot gases will then pass out through the flue pipe 35 which may be directed in the usual manner through the warehouse and out through a suitable opening in one of the walls.

It will be obvious to those skilled in the art that various changes may be made in the invention, without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claim.

What is claimed is:

A liquid fuel burner for use in a housing having a combustion space, comprising an air supply pipe extending from above downwardly, a burner element including a plate having a central vaporizing chamber provided with a circumferential series of vapor discharge apertures and an oil supply pipe leading to said vaporizing chamber, an upstanding element mounted on and projecting upwardly a short distance from said vaporizing chamber, said air supply pipe adapted to be in communication with air outside the housing and having a downwardly directed discharge end of smaller periphery than said circumferential series of openings, and located adjacent said vaporizing chamber within the circumferential series of vapor discharge apertures, a laterally extending member on the air supply pipe and located closely adjacent to the discharge opening of said air supply pipe for support upon said upstanding element, a shoulder on said upstanding element closely adjacent said chamber and adjustable relative to said vaporizing chamber and cooperating with said laterally extending member for accurately spacing said discharge opening of said air supply pipe from said vaporizing chamber discharge outlets, means for accurately adjusting the location of the shoulder on said upstanding element relative to said vaporizing chamber and thereby adjusting the distance between said discharge end of said air supply pipe and said burner whereby the amount of air may be accurately controlled for maximum efficiency, said laterally extending member adjacent the discharge end of said air supply pipe resting directly on said shoulder of said upstanding element closely adjacent said vaporizing chamber whereby temperature differences do not materially change the effective size of the discharge op ening formed by the discharge end of said air supply pipe and the burner.

References Cited in the file of this patent 5 Number UNITED STATES PATENTS Liddell Apr. 18, 1911 Number 6 Name Date Felten Nov. 2, 1915 Falkenwalde Oct. 7, 1919 Teseh Nov. 1, 1921 Hiett Aug. 3, 1926 Wolcott May 31, 1927 Peeker Dec. 6, 1927 Dov/less July 6, 1948 Kittrell Nov. 9, 1948 Strickland Apr. 3, 1951 Duncan Apr. 3, 1951 

